Acne is a common skin condition that is characterized by areas of seborrhea (scaly red skin), comedones (blackheads and/or whiteheads), pimples (papules and/or pustules), and possibly scarring. A person may display some or all of these features at once or over a period of time as multiple lesions transition through the different stages of development.
Acne begins as the result of the abnormal regulation of cells within a hair follicle, including the overstimulation of the sebaceous gland of the follicle to produce excess sebum. This causes the formation of what is referred to as a microcomedone. Once the microcomedone forms, it impedes the removal of dead skin cells and sebum from the pore. The resultant collection of dead skin cells and sebum creates an environment that is conducive to the growth and multiplication of propionbacterium acnes (P. acnes) bacteria. It is important to note that microcomedones cannot be seen or felt, in which case a conventional examination of the skin, even by an experienced dermatologist, will not reveal their presence.
As the P. acnes bacteria grow and multiply, the microcomedone grows and becomes a closed comedone or white head. Then, as the top of the white head opens, an open comedone or blackhead forms. The characteristic dark color of the blackhead results from the oxidation of melanin present in the sebum as it is exposed to air.
As the bacteria grow and multiply in the plugged follicle, they release substances that attract white blood cells, which in turn release compounds that induce inflammation. This causes a papule, which typically appears as a red bump on the surface of the skin.
As the bacteria continue to multiply and grow, more white blood cells are attracted to the follicle, causing further inflammation. The papule thus becomes a pustule and appears as an enlarging red bump with a white center. If the wall of the follicle ruptures, a larger lesion occurs. This is considered to be a large, very inflamed pimple on its way to becoming a cyst or nodule. Scarring may also result.
Treatment of acne typically depends on its severity and ranges from routine cleansing and the topical application of cleansers to the drainage of large pimples and cysts, the application of antibiotic gels, creams, or lotions, prescription retinoids, and the oral administration of antibiotics and retinoids.
Generally, to obtain the maximum benefit of treatment and to minimize damage to the skin from acne, treatment should be started as early as possible in the development of acne. Unfortunately, effective early detection or prediction of acne development is currently lacking, particularly since the early stages of acne, as characterized by microcomedones, are not visible or palpable.